A wide variety of compositions are known in the art for providing cosmetic and/or pharmacologic benefits to human skin. Benefits sought include, for example, prevention, treatment or amelioration of environmental or age-related damage or deterioration of the skin, improved appearance by modifying surface characteristics, improved feel by moisturizing, and prevention or treatment of specific skin disorders.
It is now generally recognized that exposure to solar radiation can have adverse health consequences, sometimes not appearing until several years following the exposure. Of course, the immediately appearing “sunburn” from an overexposure can itself be a serious acute health problem.
Products are available to reduce the amount of solar ultraviolet radiation received by the skin during exposure to the sun's rays. Typical product formulations are lotions, creams, ointments, or gels containing chemical and/or physical barriers to ultraviolet transmission. These vary considerably in their abilities to protect the skin against the physical and biochemical effects of ultraviolet radiation.
Earlier sunscreening formulations were designed to protect against sunburn from a limited solar exposure period, while transmitting sufficient radiation to permit skin tanning. However, the current focus is on eliminating as much ultraviolet exposure as possible, it being recognized that skin tanning, while esthetically pleasing to some, is a clear indication of tissue damage from overexposure to solar radiation. It has been recently discovered that any amount of unprotected exposure can potentially cause immune system suppression and lead to future health problems, such as skin carcinomas and other dermatological disorders.